Antioxidant Capacity and Phenolic Content of Chilies

Abstract

The antioxidant capacity of red and green Prik Khee Nu (Capsicum frutescens Linn.), and red and green Prik Chee Fah (Capsicum annuum Linn. var. acuminatum Fingerh.) which have been normally used in Thailand as a food ingredient was estimated by three different methods; Ferric reducing antioxidant power (FRAP) assay, Improved ABTS radical cation decolorization assay, and DPPH free radical scavenging activity; together with their total phenolic content. Percentages of 95% ethanol in extraction solvents were also studied. Solvents with 60 and 80%(v/v) of 95% ethanol gave higher results for all samples and methods. FRAP values of all samples calculated on the basis of mg vitamin C per gram of fresh weight were 0.62 ± 0.15 to 2.40 ± 0.13 (red Prik Khee Nu > green Prik Khee Nu and red Prik Chee Fah > green Prik Chee Fah). Values of ABTS calculated on the basis of mg vitamin C per gram of fresh weight were 1.32 ± 0.05 to 6.68 ± 0.84 (red and green Prik Khee Nu > red Prik Chee Fah > green Prik Chee Fah). Values of DPPH calculated on the basis of mg vitamin C per gram of fresh weight were 0.36 ± 0.04 to 1.23 ± 0.31 (red Prik Chee Fah > red and green Prik Khee Nu > green Prik Chee Fah). Total phenolic content calculated on the basis of mg gallic acid per gram of fresh weight was 0.85 ± 0.20 to 3.48 ± 0.58 (red Prik Khee Nu > green Prik Khee Nu > red Prik Chee Fah > green Prik Chee Fah). Correlations of all antioxidant capacity results and total phenolic content (r = 0.310 - 0.909) were found highly significant (p≤0.01).